feat: add live config profile refresh

- Standardize built-in tool users for shared writable profile mounts
- Mount canonical non-Git profile sources across compatible instances
- Report restart-required outcomes and guard active profile deletion
- Surface restart feedback in config profile editing

Quality gates: frontend build passed; backend py_compile and LSP passed.
Skipped: backend pytest/Ruff unavailable; Docker/manual checks not approved.

apps/api/src/services/config/config_profile_resolver.py

@@ -6,6 +6,7 @@ and cycle protection.
 
 import logging
 import os
+import tempfile
 import uuid
 from dataclasses import dataclass, field
 from typing import Any
@@ -481,6 +482,7 @@ def apply_resolved_profile(
     instance_dir: str,
     resolved: ResolvedProfile,
     home_dir: str = "/root",
+    working_dir: str | None = None,
 ) -> tuple[dict[str, str], dict[str, str], list[dict], dict[str, Any]]:
     """Apply a resolved profile to an instance directory.
 
@@ -489,6 +491,8 @@ def apply_resolved_profile(
     Args:
         instance_dir: Path to the instance directory.
         resolved: The resolved profile.
+        home_dir: Container home directory used for path expansion.
+        working_dir: Container working directory for top-level profile files.
 
     Returns:
         Tuple of (env_vars, files, volume_mounts, runtime_hints).
@@ -501,49 +505,57 @@ def apply_resolved_profile(
 
     instance_path = Path(instance_dir)
     env_vars = dict(resolved.env_vars)
-    files = dict(resolved.files)
+    working_dir = working_dir or home_dir
     volume_mounts = []
 
-    # Write profile files to instance directory
-    for file_path, content in files.items():
-        full_path = instance_path / file_path
-        try:
-            full_path.resolve().relative_to(instance_path.resolve())
-        except ValueError:
-            logger.warning(
-                "Profile file path escapes instance directory: %s", file_path
-            )
-            continue
-        full_path.parent.mkdir(parents=True, exist_ok=True)
-        full_path.write_text(content)
+    # Profile content belongs to the profile, not an individual tool instance.
+    # Keeping it beside the instance root gives every compatible instance the
+    # same host source while retaining the existing instance storage setting.
+    profile_dir = instance_path.parent / "config-profiles" / str(resolved.profile_id)
+    files_dir = profile_dir / "files"
+    mounts_dir = profile_dir / "mounts"
 
-    # Stage mount directories and prepare directory-level volume mounts.
-    # Each ResolvedMount targets a container directory; we stage all of its
-    # files under a single host directory and bind-mount that directory. This
-    # keeps the target directory writable by the container user, instead of
-    # having Docker create a root-owned parent directory when only individual
-    # files are mounted.
+    def write_canonical_file(root: Path, relative_path: str, content: str) -> Path | None:
+        path = root / relative_path
+        try:
+            path.resolve().relative_to(root.resolve())
+        except ValueError:
+            logger.warning("Profile file path escapes canonical storage: %s", relative_path)
+            return None
+        path.parent.mkdir(parents=True, exist_ok=True)
+        with tempfile.NamedTemporaryFile(
+            mode="w", encoding="utf-8", dir=path.parent, delete=False
+        ) as temporary_file:
+            temporary_file.write(content)
+            temporary_path = Path(temporary_file.name)
+        temporary_path.replace(path)
+        return path
+
+    # Top-level profile files are individual bind mounts under the working
+    # directory. They therefore cannot mask the workspace directory itself.
+    for file_path, content in resolved.files.items():
+        canonical_file = write_canonical_file(files_dir, file_path, content)
+        if canonical_file is None:
+            continue
+        volume_mounts.append(
+            {
+                "source": str(canonical_file),
+                "target": os.path.normpath(os.path.join(working_dir, file_path)),
+                "type": "bind",
+                "readonly": False,
+            }
+        )
+
+    # Explicit profile mounts remain directory-level bind mounts, but use the
+    # same profile-scoped canonical source for every instance.
     for mount in resolved.mounts.values():
         if not mount.files:
             continue
 
-        expanded_target = os.path.normpath(
-            expand_container_path(mount.target, home_dir)
-        )
-        mount_dir = (
-            instance_path / "mounts" / expanded_target.lstrip("/").replace("/", "_")
-        )
-        mount_dir.mkdir(parents=True, exist_ok=True)
-
+        expanded_target = os.path.normpath(expand_container_path(mount.target, home_dir))
+        mount_dir = mounts_dir / expanded_target.lstrip("/").replace("/", "_")
         for file_path, content in mount.files.items():
-            full_path = mount_dir / file_path
-            try:
-                full_path.resolve().relative_to(mount_dir.resolve())
-            except ValueError:
-                logger.warning("Mount file path escapes mount directory: %s", file_path)
-                continue
-            full_path.parent.mkdir(parents=True, exist_ok=True)
-            full_path.write_text(content)
+            write_canonical_file(mount_dir, file_path, content)
 
         volume_mounts.append(
             {
@@ -554,7 +566,9 @@ def apply_resolved_profile(
             }
         )
 
-    return env_vars, files, volume_mounts, resolved.runtime_hints
+    # Files are now mounted directly from canonical storage, not copied into
+    # the instance directory for write_config_files().
+    return env_vars, {}, volume_mounts, resolved.runtime_hints
 
 
 def expand_container_path(path: str, home_dir: str) -> str: